Vibrating actuator

ABSTRACT

A vibrating actuator is disclosed, comprising: a magnetic part including at least two magnets ( 1 ) arranged with same polarities facing each other; a receiving part including a hollow member ( 4 ) with a cavity ( 5 ) for receiving the magnetic part and at least one coil ( 2 ) wrapped around the hollow member ( 4 ) and fixed thereto; elastic elements ( 6 ) interconnecting the magnetic part and the hollow member ( 4 ); and a chassis ( 7 ). In one aspect, the magnetic part is fixed to the chassis ( 7 ) via attachment elements ( 8, 10 ) such that the magnetic part, the attachment elements ( 8, 10 ) and the chassis are stationary, and the receiving part performs a linear movement with changing direction causing the vibration when an alternating current passes through the coil(s) ( 2 ). In another aspect, the elastic elements ( 6 ) are flat elastic metal or plastic membranes ( 6 ). In yet another aspect, a magnetic guidance member of ferromagnetic material partly surrounding the hollow member ( 4 ) and the coil(s) ( 2 ) is mounted to the longitudinally outer ends of the magnetic part.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to German Patent Application No.1020151115271, filed on Jul. 16, 2015, entitled “Vibrating Actuator,”which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

The present invention is directed to a vibrating actuator for a varietyof applications, for example, a miniature vibrotactile actuator forhigh-definition haptic feedback to create immersive experiences forvideo, gaming and music and other immersive experiences.

BACKGROUND

The majority of music we traditionally listen to can be regarded ascomplex signals resulting from the addition of several signals, e.g.,mixed music signals of multiple instruments or voices. With thepossibility of electronically recording and reproducing sound, inparticular, complex music signals, a further aspect becomes important,namely, the conversion of electric signals to sound waves which areperceived by the listener when the sound is reproduced. In order toreduce distortion problems during reproduction, U.S. Pat. No. 3,118,022discloses an electroacoustic transducer comprising two conductivemembers, a diaphragm which includes electret and conductive materialsand which is supported between the two conductive members, and amechanism for electrically connecting to said diaphragm and the twoconductive members.

On the other hand, the coupled perception of sound and vibration is awell-known phenomenon. Sound is a mechanical wave that propagatesthrough compressible media such as gas (air-borne sound) or solids(structure-borne sound), wherein the acoustic energy is transported viavibrating molecules and received by the vibrating hair cells in thelistener's cochlea. Vibration, on the other hand, is a mechanicalstimulus which excites small or large parts of the perceiver's bodythrough a contact surface. The coupled perception of sound and vibrationis based on the fact that the human brain receives sound not onlythrough the ears, but also through the skeleton—measurements in aconcert hall or church confirm the existence of whole-body vibrations.The body perception of low frequencies is particularly important for animmersive experience of live music or any music sensation that isdesired to be pleasurable.

Accordingly, high-definition haptic feedback could be used to createimmersive experiences for video, gaming and music and other immersiveexperiences where the vibration is coupled to continuous audible (orvisual) signals. Major requirements for a device to achieve continuoushigh-definition haptic feedback are:

1. large frequency range, ideally from 20 to 1000 Hz, to be able togenerate good quality vibrations over this range, in particular, formusic;2. heavy moving mass, for effective acceleration;3. small, especially flat, size to make the device portable or wearable;4. high power efficiency to enable uninterrupted use;5. silent vibration to avoid disturbance of the sound experience;6. steady performance to enable continuous use;7. cost efficient manufacturing to provide an affordable device.

Different vibrating devices to realize a general haptic experience on aperson are known. Eccentric motors use an eccentric mass which isattached to the rotating rod of a motor. These motors are widely usedand can be very small. However, they have several drawbacks. Theyoperate at a very narrow frequency range, they do not exert a highvibration force and they are not meant for continuous use, all of whichmakes them unsuitable for many uses including enhanced sound experienceand, in particular, music.

Electroactive polymers are very similar to piezoelectric motors but witha higher relative mass displacement. They are still in an early stage ofdevelopment and one of their drawbacks is that, like eccentric motors,they are not suitable for continuous use because the materials'properties and, thus, the behavior of the motor, quickly change whichmakes them unsuitable for continuous use including enhanced soundexperience and, in particular, music, as well.

Vibrotactile voice-coil or moving magnet-type actuators are normallyused in industrial applications and use a voice coil or movingmagnet-type actuator consisting of two parts one of which is moving andone of which is stationary, wherein the two parts are interconnected byan elastic attachment. The vibration is generated by the interaction ofa movable permanent magnet and a stationary coil surrounding it,wherein, due to the Laplace Force, an alternating current passingthrough the coil interacts with the magnetic field of the magnet andgenerates a mechanical force with changing direction on the magnet—thisresults in a linear movement of the magnet with changing direction,causing the vibration. However, standard linear resonant actuators onlyhave a very narrow frequency range which makes them unsuitable for manyuses including enhanced sound experience and, in particular, music. EP 0580 117 A2 discloses such a moving magnet-type actuator for industrialuse in control equipment, electronic equipment, machine tools and thelike. In order to improve the performance of actuator, the stationarypart comprises at least three coils and the moving part comprises atleast two permanent magnets arranged with same poles facing each othersuch that the magnetic flux is used more effectively because a highlyconcentrated magnetic field is created in the plane between the magnets.The elastic attachment interconnecting the magnets and the coilsconsists in compression springs. However, the magnetic field lines, oncethey have crossed the surrounding coils, are lost and not guided back tothe magnets which results in waste of potential magnetic field.Furthermore, like all industrial vibrators, this actuator is noisy whichmakes it unsuitable for many uses including enhanced sound experienceand, in particular, music. US 2014/0346901 A1 discloses a similar movingmagnet-type actuator for industrial applications also with a moving partcomprising permanent magnets arranged in such a way that same poles faceeach other—however, the elastic attachment does not consist incompression springs but in resilient diaphragms. Like in the actuatoraccording to EP 0 580 117 A2, there is still a waste of potentialmagnetic field due to the loss of magnetic field lines, and the actuatoris noisy which makes it unsuitable for many uses including enhancedsound experience and, in particular, music, as well.

Thus, in view of the prior art discussed above, there is still a needfor a vibrating actuator which overcomes the drawbacks of the prior artmentioned above and which can be used in a variety of applicationsincluding high-definition haptic feedback to create immersiveexperiences for video, gaming and music by satisfying the requirementsmentioned above.

SUMMARY OF THE INVENTION

An object of this invention is to provide a vibrating actuator for avariety of applications, including haptic feedback, which provides for alarge frequency range, a high vibration force, small size, high powerefficiency, silent vibration, steady performance and cost efficientmanufacturing.

In one aspect, the present invention provides a vibrating actuator,comprising: a magnetic part including at least two magnets arranged withsame polarities facing each other; a receiving part including a hollowmember with a cavity for receiving the magnetic part and at least onecoil wrapped around the hollow member and fixed thereto; an elasticmember interconnecting the magnetic part and the hollow member; and achassis; wherein the magnetic part is fixed to the chassis viaattachment mechanism such that the magnetic part, the attachmentmechanism and the chassis are stationary; and wherein the receiving partperforms a linear movement with changing direction causing the vibrationwhen an alternating current passes through the coil(s).

In another aspect, the present invention provides a vibrating actuator,comprising: a magnetic part including at least two magnets arranged withsame polarities facing each other; a receiving part including a hollowmember with a cavity for receiving the magnetic part and at least onecoil wrapped around the hollow member and fixed thereto; an elasticmember interconnecting the magnetic part and the hollow member; and achassis; wherein the elastic member comprise flat elastic metal orplastic membranes.

In yet another aspect, the present invention provides a vibratingactuator, comprising: a magnetic part including at least two magnetsarranged with same polarities facing each other; a receiving partincluding a hollow member with a cavity for receiving the magnetic partand at least one coil wrapped around the hollow member and fixedthereto; an elastic member interconnecting the magnetic part and thehollow member; and a chassis; wherein magnetic guidance member comprisesferromagnetic material partly surrounding the hollow member and the atleast one coil are mounted to the longitudinally outer ends of themagnetic part.

The present invention also provides a method for manufacturing avibrating actuator, comprising the following steps: assembling amagnetic part by assembling at least two magnets in a dedicated assemblyjig using at least one rod, wherein the magnets face each other with thesame polarity and have a gap between them; assembling a moving part bywrapping at least one coil of self-bonding copper wire around a hollowmember comprising two slots with the coil(s) located in thelongitudinally central part of the hollow member between the slots, andheating the coil(s) and the hollow member such that the coil(s)become(s) solid and bind(s) with the hollow member; inserting themagnetic part into the moving part; attaching the elastic material tothe longitudinally outer ends of the magnetic part and to the outer endsof the hollow member; attaching the magnetic part to a chassis viaattachment members extending through the slots in the hollow member.

Further advantageous features can be obtained from the specification andthe claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective top view of the vibrating actuator;

FIG. 2 shows the view from FIG. 1 in a horizontal cross section;

FIG. 3 shows a vertical cross section of the vibrating actuator;

FIG. 4 shows a perspective bottom view of the vibrating actuator.

DETAILED DESCRIPTION

The present invention is directed to a vibrating actuator for a varietyof applications. In an exemplary application, a vibrotactile voice-coilor moving magnet-type actuator for high-definition haptic feedback tocreate immersive experiences for video, gaming and music and otherimmersive experiences is connected to an audio device via an amplifierlike a loudspeaker and via an additional low pass filter to limit theaudio frequency range to the tactile perceptible range of the skin. Theactuator can be worn, for example, around the user's wrist or other bodypart like a bracelet.

Structure of the Actuator

In one aspect, the present invention provides a unique structure of avibrating actuator. According to the present invention, the actuatorcomprises magnets 1, at least one coil 2, a hollow member 4 with acavity 5 and a chassis 7, wherein the moving part is the externalarrangement comprising the coil(s) 2 and the member 4 and the stationarypart comprises the internal magnets 1 and the chassis 7. When analternating current passes through the coil(s) 2, it interacts with themagnetic field of the magnets 1 and generates a mechanical force withchanging direction on the moving part comprising the coil(s) 2 and thehollow member 4—this results in a linear movement of the moving partwith changing direction, causing the vibration. The vibration is strongbecause the moving part comprising the coil(s) 2 and the member 4 hasmore volume and, thus, more mass, than the internal part comprising themagnets 1. Accordingly, compared to prior art devices, the inventiveactuator results in a better vibratory performance without changing theoverall size and mass of the actuator—which is important if theactuator, in particular, shall be portable or wearable. The structureand functioning of the inventive actuator will now be explained in moredetail with reference to FIG. 1-4 which show different views of theactuator.

The stationary part of the actuator contains the at least two magnets 1having at least one gap in between, wherein the magnets 1 are arrangedwith same polarities facing each other, i.e., north facing north orsouth facing south, to create a highly concentrated magnetic field inthe plane between them. The gap(s) between the magnets can be filledwith at least one spacer 3 made from a nonmagnetic material. Thearrangement of magnets 1 is attached to the chassis 7 by two attachmentmembers 8 made of a material which can be the same material as thechassis, wherein the chassis 7 can be a bracelet (which is worn by auser) or at least a casing containing both the actuator and furtherelectronics. The attachment members 8 may, for example, facilitate a“clip-in” type attachment and ensure that the arrangement of magnets 1remains stationary (by attaching it to the chassis) and maintains theposition of the area(s) where the same polarities of the at least twomagnets 1 face each other (to create the magnetic field). The attachmentmembers 8 are attached to attachment members 10 on one side thereof (forexample, the underside), wherein the attachment members 10 are attachedto the longitudinally outer ends of the arrangement of magnets 1.Accordingly, the stationary part comprises the magnets 1, the optionalspacer(s) 3, the chassis 7 and the attachment members 8 and 10.

The moving part of the actuator contains the hollow member 4 which isthe moving mass—consequently, it is made of a heavy and dense, resp.,metal because the larger the mass, the better the vibratory performanceof the actuator. As mentioned above, the moving mass, i.e., the hollowmember 4 carrying the at least one coil 2, is shaped depending on theshape of the magnets 1 such that the gap between the coil(s) 2 and themagnets 1 is relatively small in order to reduce the loss of magneticforce. For example, the internal cavity 5 of the hollow member 4 and itsouter contour should be flat and oblong if the arrangement of themagnets 1 is flat and oblong, or the internal cavity 5 of the hollowmember 4 and its outer contour should be cylindrical and oblong if thearrangement of the magnets 1 is cylindrical and oblong—of course, therehas to be certain spacing between the arrangement of the magnets 1 andthe inner surfaces of the hollow member 4 defining its internal cavity 5to enable the arrangement of magnets 1 to move within the cavity 5.Slots 9 extend through one side (for example, the underside) of thehollow member 4 in its longitudinal direction to receive the attachmentmembers 8 for connecting the arrangement of magnets 1 to the chassis 7as mentioned above in connection with the stationary part. Since thelinear movement of the moving part occurs along the longitudinal axis ofthe actuator (i.e., the longitudinal axis of the arrangement of magnets1 and the hollow member 4, resp.), the slots 9 should be relatively belong—and the extension of the attachment members 8 should be relativelyshort—enough in longitudinal direction to facilitate the movement of themoving part and, thus, the vibration. Each end of the oblong hollowmember 4 is open (the hollow member 4, thus, forming a tube) to allowattachment of elastic elements 6 (see below) to both the attachmentmembers 10 at the longitudinally outer ends of the arrangement ofmagnets 1 and the hollow member 4 on both ends thereof. The elasticelements 6 allow the moving part to perform its longitudinal movementback and forth without hitting the stationary part, i.e., thearrangement of magnets 1, the chassis 7 and the attachment member 8. Inaddition to the hollow member 4 the moving part also comprises the atleast one coil 2 which is wrapped around the hollow member 4, bothtogether creating one moving piece. Attaching the coil(s) 2 to thehollow member 4 can be achieved, for example, by some form of heattreatment during manufacture. In its resting position on the hollowmember 4, the coil(s) 2 surround(s) at least the area(s) where the samepolarities of the at least two magnets 1 face each other (see above) butnot the whole length of the arrangement of magnets 1. Accordingly, themoving part comprises the at least one coil 2 and the hollow member 4.

The elastic elements 6 essentially form the interface linking thestationary part (i.e., the magnets 1, the optional spacer(s) 3, thechassis 7 and the attachment members 8 and 10) and the moving part(i.e., the hollow member 4 and the at least one coil 2). The elasticelements 6 are attached to the attachment members 10 (which are locatedat the longitudinally outer ends of the arrangement of magnets 1) andtwo longitudinal “kebab” rods 11 (see below) passing through theattachment members 10, the magnets 1 and the optional spacer(s) 3. Theattachment of the elastic elements 6 to the hollow member 4 can beobtained by using glue or rivets, wherein the outer contour of theelastic elements 6 is the same as the outer contour of the hollow member4 (seen in a transversal cross section). Accordingly, the elasticelements 6 are fixed to the hollow member 4 at their peripheral edgesand to the attachment members 10 in the center. In order to allowsufficient movement of the moving part (i.e., the at least one coil 2and the hollow member 4) to create the vibration, the elastic elements 6have to be highly flexible.

The structure of the inventive actuator as described above has severaladvantages. Firstly, it results in a better vibratory performancewithout changing the overall size and mass of the actuator—which isimportant if the actuator shall be portable or wearable. Secondly, ifthe magnets 1 were the moving part, as is the case in the prior art,their trajectory could be distorted such that they could even hit thestationary part when the actuator is placed near a metallic surface(which can easily happen if it is portable or wearable) because themagnets are attracted by the metallic surface. This would createfriction and, therefore, inefficiency of the actuator. Because,according to the present invention, the magnets 1 are stationary andkept in place, a metal surface coming near the actuator does not affectits functioning because the coil(s) 2 and the hollow member 4 (whichform the moving part) are unaffected by the metallic surface as they arenot magnetized and, thus, do not change their trajectory.

Membrane

In another aspect, the present invention provides novel membranesinterconnecting the moving and stationary parts of the actuator. Asindicated above, the moving and stationary parts of vibratingmagnet-type actuators are interconnected by elastic elements 6 acting asspring-dampeners for the vibration, wherein the elastic elements 6 areattached to the attachment members 10 (which are located at thelongitudinally outer ends of the arrangement of magnets 1) in the centerand to the hollow member 4 at their periphery by using glue or rivets.The elastic elements 6 should allow relatively much displacement toobtain strong vibration, but at the same time occupy relatively littlespace if the actuator shall be portable or wearable. Thus, flat elasticmembranes 6 appear to be ideal for these purposes.

The membranes 6 according to the present invention are shown in FIG.1-4. They are very thin, i.e., having an approximate thickness of 0.1mm. Furthermore, it has been found out that a highly flexible metallicmaterial, for example, copper beryllium, results in an almost idealbehavior of the membranes: The alignment between the moving and thestationary parts of the actuator is much more accurate with metallicmembranes than with prior art compression springs or non-metallic (forexample, rubber) membranes and results in guiding the moving part muchmore accurately through its trajectory as it vibrates—when using priorart material such as rubber, the moving part will wiggle and movethrough its trajectory with the result that the moving and stationaryparts clash as the moving part moves through its trajectory to createthe vibration, which, in turn, creates noise and friction, the lattermaking the actuator less efficient. Therefore, by achieving the smoothtrajectory allowed by the metallic membranes according to the presentinvention, the actuator becomes both more efficient, as far as thevibratory performance is concerned, and quieter. However, if costefficiency is required, plastic membranes can also be used as long asthey are flat.

In particular for reproducing music and sound in general, respectively,it is of special importance that the actuator is relatively quiet. Theactuator noise can be reduced further by using perforated flat membranes6. All membranes disperse air when they flex to allow the moving part tovibrate. By using perforated membranes—in contrast to the prior artsolid membranes—less air is dispersed and, thus, the actuator becomesquieter.

In the following, it will be described in more detail how the membranes6 according to the present invention are arranged and how they work ifthey are additionally perforated. Membranes are elastic beams and, thus,flex like a beam one end of which is fixed, for example, to a desk andthe other end of which freely extends beyond the desk and flexes. Theouter (peripheral) edges of the inventive membranes 6 are attached tothe moving part (i.e., the hollow member 4 carrying the at least onecoil 2). The perforation of the membranes 6 can consist in a C-shapedhole 12 (in case the arrangement of magnets 1 and the hollow member 4are cylindrical) or in a U-shaped hole 12 (in case the arrangement ofmagnets 1 and the hollow member are rectangular) tracking three sides ofthe membranes' edges and creating a “peninsula” of metal in the middleof the membranes 6. This “peninsula” is attached to the attachmentmembers 10 (which are located at the longitudinal outer ends of thearrangement of magnets 1). Accordingly, if the perforated membranes areused with a prior art actuator, the “peninsulae” act like the free endof a beam (which is flexed because it moves with the moving part) andthe remaining part of the membranes 6 acts like the fixed end of thebeam; if the perforated membranes 6 are used with the inventive actuatordescribed above, the “peninsulae” act like the fixed end of the beamabove and the remaining part of the membranes 6 acts like the free endof the beam which is flexed because it moves with the moving part.

Magnetic Guidance Mechanism

In yet another aspect, the present invention provides a guidancemechanism for the magnetic field. As indicated above, in vibratingmagnet-type actuators several magnets 1 can be arranged facing eachother with the same polarity to allow a high concentration of magneticfield to be generated inside the at least one coil 2. However, once themagnetic field crosses the surrounding coil(s), the magnetic field linesare lost because they are not guided back to the magnets. It has beenfound out that, by using an appropriate magnetic circuit, most of thispotentially wasted magnetic field can be guided back to the magnets 1and used to generate additional force and, thus, stronger vibration. Dueto the use of the magnetic circuit, the vibratory performance of theactuator can be increased without having to increase the size of themagnets 1—or, if size matters, the volume of the magnets 1 (and, thus,the volume of the actuator) can be reduced compared to prior artactuators without losing vibratory performance.

In the following, it will be described in more detail how the magneticguidance mechanism according to the present invention are arranged andhow they work. Without any additional guidance magnetic field lines passthrough the coil(s) 2 and, eventually, will be attracted back to theopposing polarity of the magnets 1. Accordingly, if the magnets 1 in theactuator are arranged facing each other north to north (see above), thefield lines created in the area(s) where the magnets 1 face each otherwill pass through the coil(s) 2 and then arch back to the closestmagnet's south polarity. However, these field lines will be quitedispersed and, thus, much of the magnetic field will be lost because themagnetic field lines created in the area(s) where the magnets 1 faceeach other may take a path of several meters to travel from there to thenearest opposite polarity—even though this pole is only a fewmillimeters away. The magnetic circuit serves to guide these “wasted”magnetic field lines back to the magnets: essentially, its purpose is toensure that the magnetic field lines created in the area(s) where themagnets 1 face each other take a shorter route back to the magnets 1.This is achieved by attaching a piece of ferromagnetic material to eachof the longitudinally outer ends of the arrangement of magnets 1. Thepieces of ferromagnetic material have a U-shape, i.e., they extend a bitoutwardly from the arrangement of magnets 1, then radially outsidebeyond the hollow member 4 and the coil(s) 2 and then longitudinallyinward again up to the area(s) where the magnets 1 face each other. Inthis way, the magnetic field lines are captured when they have passedthrough the coil(s) 2 and then guided straight back to the magnets 1.Furthermore, since the magnetic circuit is (i) located close to thearea(s) where the magnets 1 face each other and (ii) made offerromagnetic material, the magnetic field lines created in the area(s)where the magnets 1 face each other are attracted by the magneticcircuit—accordingly, those field lines created in the area(s) where themagnets 1 face each other which would normally get lost right away andnot even pass through the coil(s) 2 are now attracted by theferromagnetic material of the magnetic circuit which is located at theother side of (i.e., around) the coil(s) 2. As a result, more magneticfield lines pass through the coil(s) 2, and a stronger electromagneticforce is created which, in turn, makes the actuator more efficientbecause it uses a larger amount of the magnetic field.

Manufacturing Method

The manufacturing method for the inventive actuator as described aboveis as follows:

-   -   assembling the magnetic part by assembling at least two magnets        1 in a dedicated assembly jig using at least on rod, wherein the        magnets 1 face each other with the same polarity and have a gap        between them;    -   assembling the moving part by    -   wrapping at least one coil 2 of self-bonding copper wire around        a hollow member 4 comprising two slots 9 with the coil(s) 2        located in the longitudinally central part of the hollow member        4 between the slots 9, and    -   heating the coil(s) 2 and the hollow member 4 such that the        coil(s) 2 become(s) solid and bind(s) with the hollow member 4;    -   inserting the magnetic part into the moving part;    -   attaching elements 6 from an elastic material to the        longitudinally outer ends of the magnetic part and to the outer        ends of the hollow member 4;    -   attaching the magnetic part to the chassis 7 via attachment        members 8 extending through the slots 9 in the hollow member 4.

The gap(s) between the at least two magnets can be filled by spacer(s) 3made of a nonmagnetic material such as brass, aluminum or plastic.

If the actuator shall be provided with the novel membranes 6 describedabove, it includes the further step of

-   -   laser cutting membranes 6 from an elastic material before the        step of attaching elements 6 from an elastic material to the        longitudinally outer ends of the magnetic part and to the outer        ends of the hollow member 4. The membranes 6 can be made of        metal such as copper beryllium.

If the actuator shall be provided with the magnetic guidance mechanismdescribed above, it includes the further steps of

-   -   high pressure molding of magnetic guidance elements from ferrite        material;    -   gluing the magnetic guidance mechanism to the longitudinally        outer ends of the magnetic part;        after the step of attaching elements (6) from an elastic        material to the longitudinally outer ends of the magnetic part        and to the outer ends of the hollow member (4).

As mentioned above, the inventive vibrating actuator can be used in avariety of applications including, but not limited to, high-definitionhaptic feedback to create immersive experiences for video, gaming andmusic and other immersive experiences. Generally, the vibrator can beused in all applications where a vibratory feedback is desirable,wherein this feedback is not limited to an input to a human user but canalso be addressed to a device.

What is claimed is:
 1. A vibrating actuator, comprising: a magnetic partincluding at least two magnets arranged with same polarities facing eachother; a receiving part including a hollow member with a cavity forreceiving the magnetic part and fixed thereto; at least one coil wrappedaround the hollow member and an elastic member interconnecting themagnetic part and the hollow member; and a chassis; wherein the magneticpart is fixed to the chassis via an attachment mechanism such that themagnetic part, the attachment mechanism and the chassis are stationary;and wherein the receiving part is conformed to perform a linear movementwith changing direction causing a vibration.
 2. The actuator of claim 1,wherein a spacer comprising a nonmagnetic material is provided betweenthe magnets.
 3. The actuator of claim 1, wherein the at least one coilis wrapped around the center portion of the hollow member.
 4. Theactuator of claim 3, wherein two slots for slidably receiving theattachment mechanism extend through the hollow member outside the centerportion on a side of the hollow member facing the chassis.
 5. Theactuator of claim 1, wherein the magnetic part and the elastic memberare held together by at least one rod.
 6. The actuator of claim 1,wherein the elastic member comprise perforated flat elastic metal orplastic membranes.
 7. The actuator of claim 6, wherein the membranescomprise copper beryllium.
 8. The actuator of claim 1, wherein amagnetic guidance member comprises ferromagnetic material partlysurrounding the hollow member and the at least one coil is mounted tolongitudinally outer ends of the magnetic part.
 9. The actuator of claim6, wherein a magnetic guidance member comprises ferromagnetic materialpartly surrounding the hollow member and the at least one coil ismounted to longitudinally outer ends of the magnetic part.
 10. Avibrating actuator, comprising: a magnetic part including at least twomagnets arranged with same polarities facing each other; a receivingpart including a hollow member with a cavity for receiving the magneticpart and at least one coil wrapped around the hollow member and fixedthereto; an elastic member interconnecting the magnetic part and thehollow member; and a chassis; wherein the elastic member comprises flatelastic metal or plastic membranes.
 11. The actuator of claim 10,wherein a spacer comprises a nonmagnetic material is provided betweenthe magnets.
 12. The actuator of claim 10, wherein the membranes areperforated.
 13. The actuator of claim 10, wherein the membranes comprisecopper beryllium.
 14. The actuator of claim 10, wherein the magneticpart and the elastic member are held together by at least one rod. 15.The actuator of claim 10, wherein a magnetic guidance member comprisesferromagnetic material partly surrounding the hollow member and the atleast one coil is mounted to longitudinally outer ends of the magneticpart.
 16. A vibrating actuator, comprising: a magnetic part including atleast two magnets arranged with same polarities facing each other; areceiving part including a hollow member with a cavity for receiving themagnetic part and at least one coil wrapped around the hollow member andfixed thereto; an elastic member interconnecting the magnetic part andthe hollow member; and a chassis; wherein a magnetic guidance membercomprises ferromagnetic material partly surrounding the hollow memberand the at least one coil is mounted to longitudinally outer ends of themagnetic part.
 17. The actuator of claim 16, wherein a spacer comprisingnonmagnetic material is provided between the magnets.
 18. The actuatorof claim 16, wherein the magnetic part and the elastic member are heldtogether by at least one rod.
 19. A method for manufacturing a vibratingactuator, comprising: assembling a magnetic part by assembling at leasttwo magnets in a dedicated assembly jig using at least one rod, whereinthe magnets face each other with the same polarity and have a gapbetween them; assembling a moving part by wrapping at least one coil ofself-bonding copper wire around a hollow member comprising two slotswith the at least one coil located in the longitudinally central part ofthe hollow member between the slots, and heating the at least one coiland the hollow member such that the at least one coil becomes solid andbinds with the hollow member; inserting the magnetic part into themoving part; attaching an elastic material to longitudinally outer endsof the magnetic part and to outer ends of the hollow member; attachingthe magnetic part to a chassis via attachment members extending throughthe slots in the hollow member.
 20. The method of claim 19, wherein aspacer comprising a nonmagnetic material is provided in the gap betweenthe magnets.
 21. The method of claim 19, comprising: laser cuttingmembranes from the elastic material to provide an elastic member beforeattaching the elastic material to the longitudinally outer ends of themagnetic part and to the outer ends of the hollow member.
 22. The methodof claim 21, wherein the membranes are flat and comprise copperberyllium.
 23. The method of claim 19, comprising: high pressure moldingof magnetic guidance member from ferrite material; gluing the magneticguidance member to the longitudinally outer ends of the magnetic partafter attaching the elastic material to the longitudinally outer ends ofthe magnetic part and to the outer ends of the hollow member.